Two conservation charities have today called for more tree planting despite claims they are contributing to global warming.

The Woodland Trust and The Tree Council made the appeal following a study published in Nature magazine which suggests plants and trees account for a substantial amount of methane, a major greenhouse gas.

Woodland Trust chief executive, Sue Holden, said trees have been around for millennia and insists their contribution to regulating the planet's climate and biodiversity vastly outweigh any theoretical harm.

She said: "We should not stop planting trees. Trees are hugely beneficial not detrimental to the world in the face of accelerating climate change. They absorb carbon dioxide, produce oxygen, help to dampen flood peaks, which are predicted to increase.

"They also help to regulate local temperatures and provide valuable habitats for plants and animals which will come under increased pressure from human-induced climate change as well as providing high quality green space.

"This clearly is an interesting study, but by far the biggest contributors to greenhouse gas emissions are people and their activities. What should be worrying all of us is vast increases in man-made greenhouse gas emissions that are having a drastic effect on our climate.

"Trees and woods have been around for millennia and if this study is correct, it suggests that they have always produced methane."

Ms Holden said vast areas of forest had been lost, but concentrations of greenhouse gases continued to grow.

"We should look to our own behaviour rather than placing blame on natural processes that have gone on for millennia.

"Methane is also produced by wetland habitats, livestock and people. To pursue the line that planting is harmful implies we should drain all wetlands, cull livestock and reduce the size of the human population.

"This study does not change the fact that the ancient habitats that remain desperately need our help if they are to be placed on a sustainable footing in the face of global change.

"Some of this action must involve planting trees to buffer and extend these habitats and also act as sinks for carbon dioxide. We don't need fewer trees, we need more."

Pauline Buchanan Black, director-general of the Tree Council, added: "The findings that trees emit methane would only be relevant to climate change if the benefits they bring did not significantly outweigh the negatives.

"I would suggest that anyone who, in the light of this, takes the view that tree planting is inadvisable opens their eyes to the abuses of the environment from other quarters and shifts their attention to those.

"The reality is that trees matter and we need many more trees of the right kind and in the right places."

Established in 1972, the Woodland Trust has 300,000 members and supporters and cares for around 50,000 acres of woodland.

The charity aims to preserve and increase Britain's woodlands, improve the biodiversity of woods and give people a greater understanding and enjoyment of woodland. For more information visit www.woodland-trust.org.uk

The Tree Council is dedicated to inspiring, initiating and enabling effective action for trees in town and countryside. It is an umbrella body for 150 organisations working together for trees and a forum for tackling issues relating to trees and woods. For further information visit www.treecouncil.org.uk

For cry'in out loud. Global warming has being going on since the Ice Age.

Ice Ages are intervals of time when large areas of the surface of the earth are covered with ice sheets (large continental glaciers).

The term is used to describe time intervals on two very different scales. It describes long, generally cool intervals of Earth history (tens to hundreds of millions of years) during which glaciers advanced and receded. The term also describes shorter time periods (tens of thousands of years) during which glaciers were near their maximum extent. These shorter intervals are also known as "glaciations."

In addition, the term "Ice Age" is sometimes used to refer to the last major glaciation that occurred in North America and Eurasia. When used in this way, the first letters of both words are often capitalized. This is the way the term Ice Age is used in the Midwestern U.S. 16,000 Years Ago exhibit.